#include <iostream>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#include <string.h>
#include <vector>
#include <map>
using namespace std;
using namespace __gnu_pbds;
map<int,int> m;
vector<int> v[200005];
int a[200005],b[200005],mn[200005],mx[200005],q[200005],Tree[3000005];
tree<int,null_type,greater_equal<int>,rb_tree_tag,tree_order_statistics_node_update> t;
void update(int node,int st,int en,int idx,int val)
{
if (st==en)
Tree[node]=val;
else
{
int mid=(st+en)/2;
if (st<=idx && idx<=mid)
update(2*node,st,mid,idx,val);
else
update(2*node+1,mid+1,en,idx,val);
Tree[node]=max(Tree[2*node],Tree[2*node+1]);
}
}
int query(int node,int st,int en,int l,int r)
{
if (en<l || st>r || r<l)
return -1;
if (l<=st && en<=r)
return Tree[node];
int mid=(st+en)/2;
return max(query(2*node,st,mid,l,r),query(2*node+1,mid+1,en,l,r));
}
int main()
{
int n,k;
scanf("%d%d",&n,&k);
for (int i=0;i<n;i++)
{
scanf("%d%d",&a[i],&b[i]);
m[a[i]];
m[b[i]];
mn[i]=min(a[i],b[i]);
mx[i]=max(a[i],b[i]);
}
for (int i=0;i<k;i++)
{
scanf("%d",&q[i]);
m[q[i]];
}
int cnt=0;
for (auto &i:m)
i.second=cnt++;
memset(Tree,-1,sizeof(Tree));
for (int i=0;i<k;i++)
update(1,0,2*n+k,m[q[i]],i);
for (int i=0;i<n;i++)
v[query(1,0,2*n+k,m[mn[i]],m[mx[i]]-1)+1].push_back(i);
long long ans=0;
for (int i=k;i>=0;i--)
{
if (i!=k)
t.insert(q[i]);
for (int j:v[i])
{
int cnt=t.order_of_key(mx[j]-1);
if (!i)
cnt+=(mn[j]==a[j]);
if (cnt%2)
ans+=mn[j];
else
ans+=mx[j];
}
}
printf("%lld",ans);
}
